


Reiji Smut Headcanons

by LStar



Category: Uta no Prince-sama
Genre: M/M, Plot What Plot/Porn Without Plot, Why Did I Write This?, headcanons, help him, im going to hell, oneshots, reiji is a complete subbie, reijis very cuddly after sex, take ao3 away from me, whats a continuity
Language: English
Status: In-Progress
Published: 2019-01-05
Updated: 2019-01-24
Packaged: 2019-10-04 20:41:18
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,030
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17311532
Author URL: https://archiveofourown.org/users/LStar/pseuds/LStar
Summary: Just...smut headcanons. So if you ship ReiAi, RanRei, or Camus x Reiji then here's some smut for you.I came up with these afew weeks ago and now I'm gonna write them out.These are how I view the smut would go in each ship.Also how do I title these...





	1. Ai x Reiji

**Author's Note:**

> I'm so sorry.

 

Sex is something that Reiji and Ai don't get the luxury of doing very often. Reiji doesn't mind this- Ai always has a tight knit schedule and more often than not, sex was not included. He was quite busy, from waking up at 5am, doing everything accordingly, until he goes to bed at 9pm. He hates messing his schedule up, and Reiji completely understands that. He's just glad they can still have some time to talk and, sometimes, they even cuddle at night. That was usually enough for Reiji. As long as he had his Ai-Ai, he was content. That didn't mean he doesn't think about it, oh sure when he's home alone he may lock himself in the bathroom for a quick session, but that's normal. It was nothing to be ashamed about. (Though this didn't mean he would tell people about it.)

But, there are times when Ai finishes his work early. When Reiji is already done and at home. When Ai would come home with a dissatisfied frown on his face. "It would seem my scheduling is now completely thrown off for the next three hours," he was always disturbed by this, needing absolute perfection. Reiji would offer him dinner, and Ai would help clean up. There was always still time afterwards.

"Ai-Ai," Reiji cooed as they sat on the couch. Ai looked at him, as if scrutinizing him. "I already know what you're going to suggest, Reiji," Ai said in disapproval, "I recognize that look in your eyes."

"What look?" Reiji pouted.

"That lustful, needy, begging to be fucked look," Ai was so blunt, and honestly? It was a huge shock to hear Ai cuss. Reiji gulped, feeling his pants begin to tighten. Did he really just get turned on, over Ai's soft and methodical voice _cussing_? 

Ai seemed to notice this. Of course he did. "Pervert," he uttered, shaking his head. Reiji whined, scooting closer to Ai. "We haven't done anything in months," he pouted, palming the bulge in his jeans. Ai's cyan eyes flickered to the movement, then back to Reiji's aroused gray eyes. He sighed, and managed a tiny smile. "I...suppose that's true, and I have already gathered today's data, as well as make the schedule for tomor-"

Ai was cut off by Reiji kissing him. Ai made a surprised noise from the back of his throat while Reiji slid his tongue inside of Ai's mouth. He cupped Ai's face, pleased he managed to catch the robot off guard. Ai fumbled into the kiss, causing Reiji to pull back and smirk. "Wow, Ai-Ai, are we feeling a little submissive today?" he teased. Ai's face hardened and he made a noise akin to a growl and dove in for another kiss, his tongue immediately going inside of Reiji's mouth and dominating.

Reiji didn't have a chance to fight back.

Ai pulled away after several moments, watching as Reiji's lips dripped in saliva. "We better move to the bedroom, it would be quite problematic if Ranmaru or Camus came home while we're at it," he mused, getting up. When Reiji stood, Ai grabbed his wrist and all but dragged him to the bedroom. Ai's bedroom, since it was the only one with a lock. Ai himself had made the lock.

Reiji was pushed onto the bed, with Ai climbing on top of him, removing Reiji's tie and unbuttoning his shirt. When he finished, Reiji lifted his body slightly, so Ai could remove it and discard it somewhere on the floor. Reiji moaned as Ai removed his jeans and tossed them to join his shirt and tie. Ai stared down at Reiji, a certain look that Reiji had grown to recognize and love in his eyes.

"You're so turned on," Reiji teased, "all we did was kiss."

Ai scowled at him. "I am not the one who got a boner over me saying fuck," he accused. Reiji's hips jerked, and  _how and why was he so turned on by that_?

A smirk, followed by Ai removing his own shirt and palming Reiji's hard-on through his boxers.

_It was always a repeated process. Ai would always tease him before getting to work on the real deal. Though not every time was the exact same, it was pretty similar. Sometimes Ai would bind his wrists together, other times, he'd leave them be and fuck him. They always did the same sex position- missionary. Ai always preferred to look at Reiji's face when they did it. He enjoyed seeing the new looks crossing the older man's face, and Reiji loved seeing Ai's mask breaking into one of lust and desire._

Ai removed Reiji's boxers, and his own pants and boxers. He loomed over Reiji as Reiji stared up at him, a wide grin on his face. "Come on, Ai-Ai, or I'll end up finishing myself off," he teased. Cyan eyes narrowed as he moved so Reiji's legs were spread open wide and leaned over, opening his drawer and taking out some lube. He coated his fingers with them before putting the bottle back and settling back to his spot between Reiji's legs. He prodded his finger at the entrance of Reiji's hole, and slid a finger in.

Reiji moaned at the intrusion, trying to get used to the feel of being penetrated again.

Several minutes pass before Ai enters a second finger, scissoring them around, before sliding in his third finger.

Reiji writhed and moaned. Ai always knew when to add more fingers in. Whether it was from past experience or research, he didn't know. It was most likely a mixture of both.

When Ai removed his fingers, Reiji grunted at the sudden emptiness and looked up at Ai, needy. Ai leaned over and kissed his forehead. "Don't worry, you'll have something much bigger inside of you," he murmured, grabbing the lube from his nightstand again and squirting a generous amount on his cock. Once he was properly coated, he put the lube back and turned his full attention on Reiji.

"Lift your legs," he instructed. Reiji did as he was told so Ai had better access. Ai leaned over, grabbing Reiji's legs and throwing them over his shoulders. This wasn't new, but it wasn't common. Reiji watched as Ai slowly slid his cock inside of Reiji. He threw his head back, gasping and gripping Ai's bed sheets. It stung abit, but he knew if he just relaxed, the pain would soon go away.

Ai knew this too, as he leaned over and kissed Reiji's neck, then jawline, then his lips as he slid in inch by inch. He rubbed Reiji's thighs and deepened the kiss until he was fully sheathed into him. He pulled away, his hands on either side of Reiji's head, holding himself up so he wouldn't drop onto Reiji. His cyan eyes were bright with need and arousal, as if he was focused on holding himself back until Reiji was comfortable.

When Reiji was fully relaxed, he moaned. "S-so good, so full," he wrapped his arms around Ai's neck, "please, Ai-Ai! Start moving!" he begged.

_The self control Ai usually had would always snap once Reiji was ready._

He snapped his hips forward and began pounding into him. Reiji screamed out in surprise and pleasure, gripping Ai's hair tightly. They were at such a good angle, Reiji could feel every bit of Ai's cock mercilessly throbbing and slamming into him. Within moments, Ai shifted, and began pounding against that one spot that had Reiji screaming Ai's name.

_Ai actually liked it when Reiji moaned or screamed his name. He knew he was doing a good job because of this, and the fact he was the one to reduce Reiji to this mess, it made him feel...proud._

"Ai-Aiiii! M-more, please!"

_He also loved it when Reiji begged. He was normally very calm and collected, but something about being in total control over how much pleasure Reiji got was exciting to him. Likewise, Reiji loved the fact Ai had complete control over him. He loved how Ai was able to let himself go._

Ai sped up his thrusts until it was physically impossible for him to go any faster, and harder. Reiji continued his begged screams, drool dripping down from his parted lips as his eyes squeezed shut. He felt something warm inside of him, and knew he was approaching release. Ai seemed to realize this too, and grabbed hold of Reiji's dick and began pumping it along with his thrusts.

A whole new wave of pleasure was welcomed by Reiji, screaming out Ai's name until he finally came. Cum squirted and landed on both his and Ai's chests and stomachs. Ai continued pounding into him, once, twice, again. Once, twice, again. Once, twice, again. By around the tenth thrust, he let out a warning noise and came directly inside of Reiji. Reiji's body jerked at the wonderful sensation of Ai's fluids hitting his prostate.

The two men panted, neither moving for a solid minute, catching their breath. Reiji slowly looked up at Ai, flustered, dazed, but pleased.

Ai met his gaze and went for a much calmer, loving kiss as he pulled out. Reiji winced at the sudden emptiness again, but gladly returned the kiss.

_Once they were somewhat over their orgasm high, Ai would stand up, usher Reiji to the bathroom, and help him wash up. The two would relax for a short while in the tub before getting out. Ai always had Reiji wait on the ground after helping him dry off and get dressed so he could focus on getting the sheets washed, and change the new sheets. Once that was done, he'd help Reiji to the bed, both males wrapping their arms around the other, with Reiji's face buried in Ai's shoulder._

Ai didn't care whether he was big spoon or little spoon. He only wanted to feel Reiji. Reiji didn't mind either way either. He liked having Ai in his arms, but it was always nice when he could be held too. He liked it. He liked being taken care of. It was a nice change contrasting him usually taking care of everyone outside of sex.

_Sleepy, warm kisses would be shared until one of them passed out. The other would watch them sleep for a small amount of time, before succumbing to sleep._


	2. Ranmaru x Reiji

**Summary for the Chapter:**

> Ranmaru and Reiji smut time...

**Notes for the Chapter:**

> It's been 19 days since I published this. I have little to no motivation or inspiration to writing this. But smut.

 

Sex wasn't uncommon with Reiji and Ranmaru, but it wasn't an everyday occurrence either. Hell, it wasn't even really a weekly occurrence, it was more once or twice every other week. Sometimes longer than that. Both Reiji and Ranmaru were fully grown men in the early and mid 20's, of course they're focused on work, but that work also builds up stress and hormones, and it leads to some pretty rough nights.

_Ranmaru was a stubborn top, for sure. But Reiji didn't mind._

On nights after Ai had went to his own room and gone into sleep mode, and when Camus was going to be late, Ranmaru would come into Reiji's room, his mismatched eyes staring gruffly at the older, smaller man. He crossed his arms. "We doing this or not?" that was his usual way of asking Reiji's consent for sex. It made Reiji happy, as most people would assume if Ranmaru's horny, he'll just come in, dick whipped out, ready to shove it in Reiji's ass.

Most of the time, if Reiji wasn't tired or already asleep, he'd perk up from whatever he was doing and sit up, beckoning him closer. "I'm all yours, bad boy," he teased. Ranmaru growled, moving to close the door, yanking his vest off and throwing it elsewhere before approaching the irritatingly happy man, roughly pinning him down and kissing him on the lips. His older boyfriend would moan instantly, never thrown off from how rough Ranmaru was.

Ranmaru grabbed Reiji's shirt and yanked it off, followed by his pants and boxers, moving from his lips to his neck, biting down roughly. Reiji moaned abit louder, arching back. "Haaa, Ran-Ran!" he gasped, moving to try to tug at Ranmaru's pants. Ranmaru slapped his hands away, pulling away from his neck. "Be patient, Reiji," he hissed, "I'm in control."

Reiji's cock twitched at that. Ranmaru smirked, and took Reiji's nipple in his mouth, his other hand playing with the other nipple. Reiji cried out and moaned, twitching, gasping, and mewling underneath his stronger boyfriend. Once he was done with his nipples, he removed his shirt. Reiji's gray eyes snapped to Ranmaru's...very nicely toned...muscular chest...his delicious abs...

A squeeze at his hard dick snapped him back to reality. "Hey, gay fuck, my eyes are up here," Ranmaru snorted at his soft and mildly squishy lover. Reiji whined and moaned, forcing his gaze away from Ranmaru's wonderfully made body.

Then came one of Reiji's favorite parts; Ranmaru removing his pants and boxers, leaving him fully exposed.

 _'What a sight!'_ Reiji thought each time, eyeing Ranmaru's large cock. And to think, that big thing was gonna be up his tight ass soon enough. The very thought had his own cock twitching rapidly. Ranmaru smirked. "Well, somebody's excited," he mocked, leaning over and holding three fingers to Reiji's lips. "Suck," he ordered. Reiji complied immediately, taking in all three of the digits, coating them with his warm saliva. He swirled his tongue around Ranmaru's fingers, saliva dripping from the three fingers to his hand. Ranmaru pulled his fingers out and looked at Reiji, his eyes hard.

"Turn."

Reiji quickly complied, getting on his hands and knees.

_Yes, the 'doggy style' was Ranmaru and Reiji's most common position. Ranmaru didn't hate seeing Reiji's face when they did it, he liked it, actually, but this position gave him the most pleasure, plus he got a wonderful view of Reiji's ass, and was in perfect position to give it a smack if Reiji misbehaved. The position was also perfect because Ranmaru could lean forward or yank Reiji backwards, and use his hands to tease Reiji's nipples, or even his dick, and he could still give hickies to the older man, so both Ranmaru and Reiji were more than fine with this position. They both benefited well from it, for Reiji, he could receive abunch of pleasure all at once, and for Ranmaru, he had great views and had complete control._

Reiji felt a wet finger prodding his hole and lowered the upper half of his body, so his ass was sticking up abit. He heard Ranmaru give a low growl as he slid the finger inside of him. Reiji squirmed, familiarizing himself with the feeling of being penetrated.

After a little bit of teasing, a second finger was added, and then a third. Ranmaru shoved his fingers in deep, curling them around, spreading them apart, all in preparation for his dick.

Once he deemed Reiji ready, he pulled his fingers out. Reiji whined at the emptiness, bucking his hips back abit. Ranmaru made a noise and gave his ass a firm smack. "I _said_ to be patient, didn't I?" he demanded in a low voice. Reiji made a small, affirmative noise and tried to keep still, his body was shaking in anticipation. He heard shuffling and took a quick peek at Ranmaru. He was coating his dick with- most likely saliva, so he wouldn't enter Reiji dry.

Reiji turned back around to face the wall and bedpost, burying his face in his pillow, smiling to himself. Ranmaru maybe really rough in bed, but everytime he took the time to make sure Reiji was properly lubed and prepared, it just...made him happy. It made him realize that Ranmaru, despite being cold, despite being rough, and despite not showing it very well, truly cared for his wellbeing.

He felt something hard and large press against his ass and knew it was time. He took a deep breath. He's not gonna lie, everytime Ranmaru enters him, it hurts. It stretches, despite the preparation.

_Yet...despite all of the pain...Ranmaru would still wait for Reiji to be comfortable before he does anything._

Ranmaru slid in, inch by inch, stopping whenever he heard Reiji gasp or groan in pain. When he was fully in, he waited, his hips pressed against Reiji's ass cheeks, his rough hands gripping Reiji's thighs tightly.

Reiji panted, his grip on his bedsheets tightening. "Ran-Ran, please move!" he sobbed. The pain was gone, and now he really needed  _movement._ Ranmaru let out a growl and pulled out until only his tip was in before he snapped his hips forward. Reiji moaned into the pillow loudly, drool slipping down his lips. Ranmaru ruthlessly pounded his cock into Reiji's tightening ass, going harder and faster with every thrust. "Shit, Reiji," Ranmaru snarled, yanking him back and pinching at his nipples roughly, "you're fucking tight."

Reiji only cried out in pleasure, louder than before. One of Ranmaru's hands slapped over Reiji's mouth, his hot breath tickling Reiji's ear. "Shut up, you'll wake Ai."

The chance of being caught wasn't exactly something Reiji was keen on, and yet his cock twitched at the idea anyway. Ranmaru noticed and moved his hand to it. "You're excited about that? You're so lewd," he mocked. Reiji mewled.

Ranmaru moved to shove him back onto the bed, pinning him face first on it, before continuing his rough thrusts. Reiji struggled to stifle his moans and cries, feeling that familiar warmth bubbling up. "Haaa! Ran-Ran I need to cum! Please let me cum!" he begged. A hand smacked at his ass again. "Cum then," Ranmaru growled, his voice abit more strained. He was nearing his release too.

Reiji let out a muffled shout as he came, and minutes pass before Ranmaru came with a gruff "shit" under his breath, his cum directly in Reiji's ass.

They panted, before Ranmaru pulled out and flopped next to Reiji, closing his eyes. Reiji stared at him as he slowly zonked out, biting his lip. He did wish Ranmaru would do...some aftercare, but it just wasn't him. He sighed and smiled anyway, slowly slinking in the blankets and throwing the covers over them, laying his head on Ranmaru's shoulder as he too, zonked out.

**Notes for the Chapter:**

> Wow ew I'm bad at this. This was short and shitty.

**Author's Note:**

> I'm going to hell.  
> Oh well. Comments appreciated!


End file.
